Reduced gauge bottle cap

ABSTRACT

A reduced gauged crown for a container opening includes a corrugated panel portion such that the corrugation strengthens the crown material and allows less material to be used for the crown than would be used for an uncorrugated bottle cap.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present disclosure is a continuation of U.S. patent application entitled “Reduced Gauge Bottle Cap” filed May 5, 2017, and assigned Ser. No. 15/588,263, which is a continuation of Ser. No. 14/243,437, filed Jul. 24, 2012.

FIELD OF THE DISCLOSURE

The present disclosure relates to caps and crowns for beverage bottles and other containers, and in particular, to a reduced gauge corrugated bottle cap.

BACKGROUND

Published U.S. patent application Ser. No. 12/597,385 to Merino Caballero (“Caballero”) discloses a low gauge crown cap in which the top panel exhibits grooves in various shapes, depending on the embodiment, to achieve corrugation and obtain a crown that has a low gauge of crown material such as steel. Although not prior art due a priority date subsequent to the priority date of the present disclosure, the present inventor acknowledges the Caballero application because it was published prior to the filing date of the present disclosure.

Related application Ser. No. 12/903,533, and its parent Ser. No. 11/698,247 (issued as U.S. Pat. No. 8,061,544), referenced above, disclose a bottle crown that has a seat in which rests a pull tab assembly so that the pull tab assembly is flush with the top of the crown. The seat is formed by means of a depression or recess in the top of the crown. A benefit of the recessed top is that the recess functionally acts to corrugate the top of the crown. As is well understood, corrugation has the advantage of stiffening a sheet of material against forces that are perpendicular to the direction of corrugation. That is, a corrugated sheet is harder to bend than a non-corrugated sheet, at least in certain directions. A bottle crown that has corrugation across its top will be stiffer than a non-corrugated crown. Therefore, to achieve the same degree of stiffness of a non-corrugated crown, a corrugated crown may be thinner, or have a lower gauge, of crown material such as steel or tinplate. The advantages of corrugation that are implicitly inherent in the crown of the '533 application are made explicit in the present disclosure. The present disclosure, therefore, describes a corrugated crown and the advantages thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description that follows, by way of non-limiting examples of embodiments, makes reference to the noted drawings in which reference numerals represent the same parts throughout the several views of the drawings, and in which:

FIG. 1 is an isometric side view illustration of a reduced gauge crown of the present invention.

FIG. 2A is a top view illustration of the crown of FIG. 1.

FIG. 2B is a side cross-section view of the crown of FIG. 2A.

FIG. 3A is a top view illustration of an alternative embodiment of a crown of the present disclosure.

FIG. 3B is a side cross-section view of the crown of FIG. 3A.

FIG. 4A is a top view illustration of another alternative embodiment of a crown of the present disclosure.

FIG. 4B is a side cross-section view of the crown of FIG. 4A.

FIG. 5 is an isometric side view illustration of another embodiment of a reduced gauge crown of the present invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIG. 1 is an isometric side view illustration of a reduced gauge crown of the present invention. Crown 100 includes top portion 110 contiguous with recess 120 which terminates in panel 130. Skirt 140 downwardly extends from top 110. In some specific embodiments a flange extends obliquely from skirt 140. Alternating flutes 150 and lands 152 are formed on a circumferential portion of skirt 140. Crown 100, and other crowns shown in the figures, is shown as a pry-off type that is opened with a lever. The present invention also encompasses a twist-off type (not shown in the figures) that is opened by twisting, as will be understood by persons familiar with crown cap technology. Finally, crown 100 is suitable for use with pull tab type assemblies mounted to panel 130 with effective score lines embossed on crown 100. Such an embodiment of the crown 100 configured for use with such a pull tab is discussed below with reference to FIG. 5.

Panel 130 is recessed, that is, it is lower than top 110 but is contiguous with top 110 by virtue of transition surface 120, which will be referred to herein for convenience as recess 120. Recess 120 may formed in crown 100 in a variety of suitable way to provide advantageous shapes. For example, in specific exemplary embodiments concentric tiers, grooves or steps are integrally formed in the crown 100 material until the desired depth of panel 130 is obtained, as illustrated in FIG. 1. In alternative embodiments, recess 120 is formed with a smoothly curved surface from top 110 to panel 130. The form of recess 120 functions as ribs or structural reinforcements that, it is surmised, help to stiffen panel 130 against deflection or deformation.

Skirt 140 descends from top 110 along the external perimeter of crown 100 and in specific exemplary embodiments smoothly merges into downwardly and radially outwardly extending flange. The skirt 140 is preferably adapted to be crimped onto the neck of a bottle for sealing. Specific exemplary embodiments of skirt 140 are divided into undulating, repeating portions that define the flutes 150 and lands 152. Preferably, the repeating portions are circumferentially evenly spaced apart such that each flute 150 is identical to all other flutes 150 around the circumference of the crown cap 100, and each land 152 is identical to all other lands 152 around the circumference of the crown cap 100. It should be understood that the crown cap 100 may include any number of flutes 150 and lands 152.

Referring to now to FIGS. 2A and 2B, 3A and 3B and 4A and 4B, the “B” figure of each depicted embodiment is the horizontal cross section of its “A” counterpart through line B-B. Each embodiment, designated 2A/B, 3A/B and 4A/B, is characterized by a particular diameter of its panel 130, as represented by width B 210, 310 and 410 of each embodiment, respectively, and depth A of recess 120 represented by depths 220, 320, and 420, respectively.

A specific amount of material strengthening from corrugation is achieved by selecting an embodiment with a particular combination of panel diameter 210, 310 or 410, for example, and recess depth 220, 320 or 420, for example. Exemplary embodiment 2A/B, for instance, has panel diameter 210, which is relatively wide, and recess depth 220, which is intermediately deep. Exemplary embodiment 3A/B has panel width 310, which of intermediate width, and recess depth 320, which is the deepest of the three exemplary embodiments. Exemplary embodiment 4A/B has panel diameter 410, which is the narrowest of the embodiments, and recess depth 420, which is the shallowest depth of the three embodiments. To obtain a desired amount of material strengthening from corrugation, a combination of panel width 210, 310, or 410, for example, and recess depth 220, 320 or 420, for example, is selected to achieve a specific embodiment.

Corrugation strengthens materials. This is particularly true of laminar materials formed into a sheet or plane. A laminar product can use less of a material if the material is corrugated to provide lateral strength. A bottle cap is a laminar product in which the sheet material, often steel or tin plate, is shaped to be affixed to the top of a bottle or other container. A standard pry-off or twist off cap has a thickness of material that is predominantly determined by considerations of leak prevention and the secureness of the attachment of the cap to the container.

Billions of bottle caps are used worldwide and the cost of the caps is largely determined by the amount of material required for the caps. Corrugation allows caps that use less material to have the equivalent strength of a standard thick crown, a corrugated crown is thinner, that is, it has a reduced gauge, in comparison to a standard bottle cap. An advantage of a reduced gauge cap is the money savings obtained by using less material.

Another advantage of a reduced gauge corrugated cap comes into play with innovated “pull-off” caps, which have a pull tab assembly attached to the crown as described in the related patent applications, one embodiment of which is described in detail below with reference to FIG. 5. As discussed below, the pull tab breaks the cap material and the crown is torn off the bottle using the pull tab. A reduced gauge cap facilitates the tear off because the cap material is thin and the tearing action is parallel to the direction of material strengthening provided by the corrugation and therefor the tearing force does not have to overcome the material strengthening of the corrugation. Corrugation affords material strengthening perpendicular to the direction of corrugation.

In addition to the structures illustrated in the figures herein, it is understood that other structures will imbue a cap of the present disclosure with the advantages of corrugation and provide a reduced gauge crown for a bottle. For instance, concentric rings, which progress from the top of the skirt toward the center of the panel, and decorative shapes such as stars, brand logos, sports team logos, religious insignia, and the like, formed in the plane of the cap, are embraced in the present disclosure.

Corrugation forms may be provided to a bottle cap by a variety means, including without limitation, metal stamping, pressing, embossing and so forth. Non-metal crowns of the present disclosure may be formed by injection molding for plastic crowns, or by other suitable means of production.

The crown caps 100 preferably are formed with steel of increased hardness compared with conventional crown caps presently in commercial production. For example, conventional crown caps are often formed of single reduced, T4, tinplate having a thickness of from 0.21 mm to 0.23 mm. Such tinplate has an average hardness (that is, the reported hardness value regardless of +/−variations) of approximately 61 on a 30 T hardness scale, in accordance with ASTM 623. Crown caps 100 described herein may be made thinner and lighter weight compared, with the prior art, for example, crown caps 100 may be formed of a material having a thickness of about 0.16 mm to 0.18 mm that have the same or roughly equal performance as conventional, thicker caps. These decreases in metal usage are more easily achieved when the structure of crown caps 10 are made with steel having increased hardness. For example, the inventor has demonstrated the effectiveness of low gauge crowns having grooves using DR8 (according to ASTM 623) or DR550 (according to EN 10203). Optionally, the inventor surmises that other materials may be used, such as single reduced tinplate or like material having enhance tempering, tin-free steel having similar properties as those described herein, and the like.

The crown caps 100 preferably have an average hardness of greater than 62 on the 30 T scale (conforming to ASTM 623), more preferably greater than about 65, more preferably greater than about 68, more preferably greater than about 71. The embodiments shown in FIG. 1 and FIG. 3A were demonstrated to be effective using steel having a hardness of 73. The upper limit of hardness is set by the maximum stress acceptable to the glass bottle during the crimping process or the spring back (which may tend to urge the crimped flanges toward an uncrimped state) associated with harder plate.

The crown caps 100 may be formed with conventional press equipment, with only minor changes to parts of the tooling to form the structure (such as the grooves, crosses, stars, and dimples). And crown caps 100 may be crimped with conventional equipment, only modified to have a smaller throat compared with existing, conventional crimpers.

Because hardness has a relationship to strength as reflected in the yield point, the aspect of the hardness of the crown may be expressed in yield point on a corresponding scale. For example, DR8 or DR550 tinplate may has a yield point (in a tensile test) of 550 MFA. The inventor believes that the most advantageous crown cap has a combination of one or more of the structured described herein and harder plate as described herein. A crown of the present disclosure, however, encompasses crown caps that do not have all of the structure, materials, and/or advantages in this specification.

According to this description, commercially acceptable crown caps formed according to the present disclosure can be commercially made with up to 25 percent less steel compared with many conventional crown caps, which has corresponding advantages in carbon emissions. The savings in steel weight are approximately proportionate to the reduction in metal thickness. Further, even though energy required to cool an individual crown is tiny, the energy required to cool the total number of crowns produced each year (approximately 45 billion, in North America and approximately 300 billion throughout the world) and the corresponding reduction in that energy, it significant.

In addition to the various structures described herein, certain advantages over the prior art are bestowed on the present crown by the recommended specifications shown in Table 1.

TABLE 1 Items Acceptable Range/Target_(—) 1. Appearance Disc properly adhering White liner Complete liner Clean liner Clean crown and ring No rust and scratch for crown and ring Two cut lines on the downward surface of crown Rivet Crown 2. Dimensions Thickness (mm): 0.16-0.18 Inside diameter (mm): 32.08-32.12 Outside diameter (mm): 26.60-26.90 Radius of angle (mm): 1.5-1.9 Number of angles: 21 Ring Diameter (mm): 21.1-21.5 Thickness (mm): 0.28-0.32 Liner Diameter (mm): 20.00-20.50 3. Rockwell Hardness T4 on the Rockwell 30T scale 4. Secure Seal Greater than/equal to 150 PSI for 1 minute 5. Finish Hardness Should not scratch with “H” pencil 6. Sensory No significant differences with an identified control after 12 weeks at 20 degrees C. 7. Lubricant Migration No particles or lubricant should be present 8. Simulated Palletizing CO2 loss should not differ against control caps when stored for 1 week with max weight of 45 Kgs over each bottle 9. Corrosion Maximum corrosion: slight to moderate 10. Odor No off odors detected 11. Pulling Force 2.5 kg of Ring (kg) 12. Composition of Tinplate crown and ring; food class non-PVC Material for liner 13. Package 5000 Crowns per box 14. Pressure (kg) 10 kg 15. Container Loading 1,000 Master Cartons 16. Printing Logo/other design may be printed on the Easy Pull ™ Cap 17. Crown Anti-Oxidation Material used is “food grade” PET; clear, with no odor, 1.2 UM (micrometers)

In particular, a tinplate material which, demonstrates an approximate hardness of T-4 on the Rockwell 30 T Hardness Scale is preferred for the present cap (see item 3 in table 1). This may be contrasted against the prior art which typically uses tinplate having a hardness of K-3 on the Rockwell scale. The preferred softer tinplate material requires less force to open and tear with the opener assembly of the present crown while still providing sufficient sealing of the container contents. For the purposes of this disclosure, tinplate refers the any material, including tin or tin alloys, from which a crown may be fabricated and does not necessarily mean that the crown is made from tin or a tin alloy.

FIG. 5 is an isometric side view illustration of another embodiment of a reduced gauge crown 500 of the present invention. This embodiment of a reduced gauge crown is configured for use with pull tab type assemblies mounted to the top panel 530. The pull tab apparatus is not shown in order to illustrate more plainly the cut lines 6 d and 6 e. In a preferred embodiment, one of the cut lines 6 e provides an S-curve or tail segment 6 f that extends along the skirt 540 of crown 500. S-curve 6 f may facilitate the removal of crown 500 from a container opening. In operation, a person tears from center 550 along cut lines 6 d and 6 e. When the tear reaches S-curve 6 f, the tearing force follows the S-curve away from cut line 6 d and impels the tear along cut line 6 d to terminus 560 which breaks open crown 500. Continued tearing force along S-curve 6 f pulls skirt 540 away from the container opening (not shown) and releases crown 500 from the container (not shown). Another feature illustrated in FIG. 5 is one or more spoilage indicators 570 such as dimples depressed in crown 500 and positioned so as not to be obscured by the pull ring apparatus of the present disclosure. For containers that are vacuum sealed, spoilage indicators 570 pop up in the event that the pressure seal is lost. One or more circular depressions 580 create space in the top 530 of crown 500 to seat the pull ring and the rest of the opener apparatus. Seat 580 is of sufficient depth that pull ring is substantially flush with the top 530 of crown 500. Such an embodiment advantageously is suitable for use in conventional bottle capping machines without having to retool or refit the machine.

The foregoing description is provided for the purpose of explanation and is not to be construed as limiting the invention. While the invention has been described with reference to preferred embodiments or preferred methods, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Furthermore, although the invention has been described herein with reference to particular structure, methods, and embodiments, the invention is not intended to be limited to the particulars disclosed herein, as the invention extends to all structures, methods and uses that are within the scope of the appended claims. Those skilled in the relevant art, having the benefit of the teachings of this specification, may effect numerous modifications to the invention as described herein, and changes may be made without departing from the scope and spirit of the invention as defined by the appended claims. Furthermore, any features of one described embodiment can be applicable to the other embodiments described herein.

Such embodiments of the inventive subject matter may be referred to herein, individually and/or collectively, by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept if more than one is in fact disclosed. Thus, although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.

In summary, the present disclosure describes a crown for a container opening. The crown has a top portion and an inner portion contiguous with the top portion. The inner is portion formed into a panel. An outer portion contiguous with the top portion is formed into a skirt that descends from the top portion. The crown has corrugation formed in the panel.

The present disclosure also contemplates methods for making the crown described above. Methods include the steps of shaping a sheet of crown material to provide a top portion and an inner portion contiguous with the top portion and formed into a panel. An outer portion contiguous with the top portion is formed into a skirt that descends from the top portion. The methods also include forming corrugation in the panel.

In specific embodiments the step of forming corrugation in the panel consists of forming a recess that descends from the top portion to the panel in the inner portion.

The Abstract of the Disclosure is provided to comply with 37 C.F.R. § 1.72(b), requiring an abstract that will allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment.

The description has made reference to several exemplary embodiments. It is understood, however, that the words that have been used are words of description and illustration, rather than words of limitation. Changes may be made within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the disclosure in all its aspects. Although description makes reference to particular means, materials and embodiments, the disclosure is not intended to be limited to the particulars disclosed; rather, the disclosure extends to all functionally equivalent technologies, structures, methods and uses such as are within the scope of the appended claims. 

What is claimed is:
 1. A reduced gauge crown for a pressurized container opening, the crown comprising: a top portion, an inner portion contiguous with the top portion, an outer portion contiguous with the top portion, the outer portion being formed into an annular skirt that descends from the top portion, CHARACTERIZED IN THAT: the inner portion comprises a central portion comprising a recessed panel; and the crown has a thickness gauge in the range of 0.16 mm to 0.18 mm, and material comprising the crown has an average hardness of greater than 62 on a 30 T hardness scale but less than an upper limit of hardness set by the maximum stress acceptable to the container during a crimping process or the spring back associated with a harder material; wherein the recessed panel comprises a uniform thickness across its entirety, and is parallel with the top portion but positioned entirely below a bottom surface of the top portion, the central portion comprising a concentric downward formed curved transition surface contiguously connecting the top portion and the recessed panel, the transition surface and recessed panel together stiffening the inner portion by providing material strengthening perpendicular to the direction of the downward formed recessed panel.
 2. The crown of claim 1, wherein material comprising the crown has an average hardness of greater than 65 on the 30 T hardness scale.
 3. The crown of claim 1, wherein material comprising the crown has an average hardness of greater than 68 on the 30 T hardness scale.
 4. The crown of claim 1, wherein material comprising the crown has an average hardness of greater than 71 on the 30 T hardness scale.
 5. The crown of claim 1, wherein material comprising the crown has an average hardness of greater than 73 on the 30 T hardness scale.
 6. The crown of claim 1, wherein the transition surface and recessed panel together provide material strengthening substantially equal to material strengthening provided by a crown without the central portion, and having a thickness gauge in the range of 0.21 mm to 0.23 mm and comprising material having an average hardness of approximately 61 on the 30 T hardness scale.
 7. The crown of claim 1, wherein the transition surface comprises a plurality of concave concentric rings formed downward into the top portion that progress from the a top of the skirt toward a center of the crown.
 8. The crown of claim 1, wherein the transition surface comprises a plurality of concave circular depressions formed downward into the top portion that progress from the a top of the skirt toward a center of the crown.
 9. A method for making a reduced gauge crown for a pressurized container, the method comprising: shaping a sheet of crown material to provide a top portion, an inner portion contiguous with the top portion, and an outer portion contiguous with the top portion and formed into an annular skirt that descends from the top portion; CHARACTERIZED IN THAT the method further comprises: employing crown material having a thickness gauge in the range of 0.16 mm to 0.18 mm, and having an average hardness of greater than 62 on a 30 T hardness scale; forming the inner portion into a central portion comprising a recessed panel having a uniform thickness across its entirety, and is parallel with the top portion but positioned entirely below a bottom surface of the top portion; and forming the central portion by downwardly forming a concentric curved transition surface contiguously connecting the top portion and the recessed panel such that the transition surface and recessed panel together stiffen the inner portion by providing material strengthening perpendicular to the direction of the downward formed recessed panel.
 10. The method of claim 9, wherein material comprising the crown has an average hardness of greater than 65 on the 30 T hardness scale.
 11. The method of claim 9, wherein material comprising the crown has an average hardness of greater than 68 on the 30 T hardness scale.
 12. The method of claim 9, wherein material comprising the crown has an average hardness of greater than 71 on the 30 T hardness scale.
 13. The method of claim 9, wherein material comprising the crown has an average hardness of greater than 73 on the 30 T hardness scale.
 14. The method of claim 9, wherein the transition surface and recessed panel together provide material strengthening substantially equal to material strengthening provided by a crown without the central portion, and having a thickness gauge in the range of 0.21 mm to 0.23 mm and comprising material having an average hardness of approximately 61 on the 30 T hardness scale.
 15. The method of claim 9, wherein the transition surface comprises a plurality of concave concentric rings formed downward into the top portion to descending depths that progress from the skirt toward a center of the crown.
 16. The crown of claim 9, wherein the transition surface comprises a plurality of concave circular depressions formed downward into the top portion that progress from the a top of the skirt toward a center of the crown. 